The present invention relates to absorption refrigeration systems. More particularly, the present invention relates to control systems for operating absorption refrigeration systems to prevent crystallization of absorbent solution in the refrigeration systems during periods of shutdown of the systems.
Absorption refrigeration systems, especially those employing a saline solution as an absorbent and water as a refrigerant, frequently utilize a dilution cycle to prevent crystallization of the absorbent solution in the refrigeration system during shutdown of the system. The dilution cycle usually comprises supplying refrigerant, sometimes from the refrigerant evaporator of the refrigeration system, to dilute strong absorbent solution in the generator and/or heat exchanger of the absorption refrigeration system, immediately upon shutdown of the system. A subsequent start up of the refrigeration system requires that the refrigerant supplied for dilution to the generator and/or heat exchanger be boiled off to resume regular operation of the refrigeration system. If the absorption refrigeration system is frequently cycled on and off the heat energy required to boil off the dilution refrigerant at each start up of the refrigeration system may result in a significant heat input penalty which reduces the efficiency of the refrigeration system.